Summer McIntosh, the 18-year-old Canadian swimming star, rolled to victory Sunday in the women’s 400-meter individual medley, setting a world-championship record and winning her fourth individual gold medal of the event.

American star Katie Ledecky won her seventh world title in the women’s 800-meter freestyle on Saturday, fending off the challenges of Canadian sensation Summer McIntosh and Australia’s Lani Pallister.

Ledecky won with a time of 8:05.62, both a world championships record and the fourth fastest time in the history of the 800m free. Pallister wasn't far behind (8:05.98), with McIntosh claiming bronze (8:07.29).